There are a number of medicament delivery devices patented and/or on the market that comprise a number of functions. A specific medicament device is often designed to handle a certain prescribed medicament container having a certain dose volume.
In many cases, the whole volume is emptied when the device is utilised, i.e. a stopper is specifically arranged inside the tubular medicament container which moves to a proximal end position in the course of the medicament's delivery through a medicament delivery member. This means that the medicament containers are designed to contain a certain volume of medicament that is prescribed for treatment of patients. In many cases however, the prescribed volumes or doses may vary considerably depending on the patient and the condition of the ailment to be cured by the medicament. For example, children require a much lower dose than adults.
There are then usually two ways of handling this situation. When the medicament delivery device is designed to handle a certain container size, then the container has to be filled with different volumes of medicament according to the requirements of the patient. This implies that the stopper will be positioned at different locations inside the container. In order for this to work, the device has to be modified such that the drive mechanism acting on the stopper is able to handle the different start positions of the stopper when delivering the medicament.
Alternatively, one can handle the delivery of different doses by having some sort of dose setting mechanism, whereby the user or a physician is able to set the specific dose to be delivered. There are a multitude of devices that display this type of dose setting feature. A drawback with this solution is that the dose setting feature entails a number of additional components that are designed to interact, making the device more complicated and more expensive to manufacture.
A further way to handle the different dose sizes is to design the medicament delivery device to handle a particular medicament container size. This means that a specific design is produced for each dose size. This latter option is, however very costly and cannot be justified for most drugs. For this reason, this latter solution has not been developed to any extent.
There is thus room for improvements in this technical area of handling medicaments of different dose volumes to be delivered with a medicament delivery device.